1. Field of the Invention
The present invention relates to a handover technique provided in switching to different communication systems, and more particularly, to a system and method for processing connection from a macro cellular base station to a mini type base station such as, a Femtocell base station.
2. Description of the Prior Art
Functionality of individual base stations in a wireless communication network system usually depends on the flow and features of the locations where the base stations are situated at. For example, macro cell base stations covered a large coverage are utilized in an area with sparsely distributed population and for high-speed users so as to increase the area of coverage. Conversely, a region with high density of skyscrapers and a plenty mobile communication users per building is confronted with a problem, that is the indoor areas of those buildings are poorly covered by the macro cell system network. Also, given a large number of mobile communication users, the capacity of the macro cell system tends to be inadequate.
Femtocell base stations are regarded as a way to expand the coverage of a mobile communication network and the enhancement of system's capacity, in which the Femtocell base stations can effectively overcome the aforesaid problems resulting from the macro cell base stations. However, in practice, the integration of a macro cell system and a femtocell system is seldom easily achieved. As a matter of fact, the base stations or access point devices of the femtocell system are required in a large number, further, the femtocell starts and shuts down independently and randomly. Therefore, it is impossible to acquire, in advance, any messages and operating parameters of the base station or access point devices that are closer to a nearby femtocell system which is covered within the coverage of the macro cell system; as a result, the position information of the base station or the access point device operating under the femtocell system cannot be notified to the mobile communication apparatus. In other words, after the mobile communication apparatus moves out from the coverage of the macro cell system into the coverage of the femtocell system, the mobile communication apparatus cannot stop receiving a signal from the macro cell system and start receiving a signal from the femtocell system, that is, when the macro cell system and the femtocell system integrated together, it cannot effectively switch between the macro cell system and the femtocell system.
Accordingly, it is imperative to devise a technique of switching between a macro cell system and a femtocell system.